In <ralph.1146355927D at news.arizona.edu>, ralph at ccit.arizona.edu (Ralph M Bernstein) writes:
>chan wrote:
>>>In article <3kolh2$b8k at styx.uwa.edu.au> Alec Redwood,
>>aredwood at uniwa.uwa.edu.au writes:
>>>: Can anyone tell me about TH3 cells and/or direct me to an article.
>>>>>>These cells were coined by those working in EAE model. They found high
>>TGFb producers when fed MBF orally. The cells did not fit into neat TH1
>>or TH2 so they coined the term. I think this is bunk. There is no clear
>>Th1 or Th2 anyway. These cells are far more versatile than those in
> ^^^^^^^^^^
>>>Huh?!?
>>>CD4+ TH1 cells have decidedly different cytokine production than CD4+TH2
>>cells. There is evidence that one cell type can downregulate the other
>>cell type (or phenotype, if you think they are the same cell). However,
>>it's interesting to note that Fas Ligand-mediated cytoxicity/apoptosis is
>>mediated by TH1 CD4+ cells and not the TH2 CD4+ cells (This doesn't
>>exclude the CD8+ cells from carrying on a non-calcium
>>dependent/Fas-dependent mechanism of lysis of target cells, of course.)
>>Derek,
> ok, i think i kind of agree with the ambiguities that David was
>mentioning. you say huh, but what about the inconsistancies associated with
>th1-th2 cells?
like in the _same_ disease model one lab getting th1 but
>another (competing) lab getting th2 type?
Hmm..that's pretty interesting... Curious...which two labs? I'm not too
much of a mouse immunologist, butif you point me to those papers, I'd be
happy to check 'em out.
it's neat to note the FAS
>connection, but has anyone else done that and reproducably gotten a th1
>phenotype? i mean, it does make sense that the killer enhancing th's would
Well it's been shown that you can actually have a CD4 response to a cell, but
non-lysis of the target cell, and this is attributed to a non-FasL mediated
response. Apparently, this "wrong response" doesn't enable the disease to be
properly "killed" (for lack of a better word).
>"kill" via fas and gld, but has anyone else show it? _also_, is any one
>getting closer to some sort of marker for the th's? (other than the
>suppoesed cytokine differences)
I agree...I think that currently, cytokine differences are what everyone's looking
at to determine whether there is a Th1 or a Th2 response. It has been shown
that the CD4+ cells which can cause apoptosis of target cells by a fas-
dependent mechanism _do_ "fit" with the Th1 phenotype in terms of cytokine
production.
> again, i think that the th1 cth2 "paradigm" has a way to go to be really
>accepted as undisputable. just call me a th1-th2 agnostic-i'm just waiting
>for some real good proof.
>Regards,
Derek
Derek V. Chan
chan4 at fas.harvard.edudvchan at netcom.com